Firefly Green Fuels, a UK-based company, has developed a new form of jet fuel that is entirely fossil-free and made from human waste. The company worked with experts at Cranfield University to confirm that the fuel they developed had a 90 percent lower carbon footprint than what is used in aviation today, according to the BBC. Tests by independent regulators validated that what Firefly Green Fuels has developed is nearly identical to standard A1 jet fuel.

In 2021, the company received a £2 million grant from the Department of Transport to continue developing its sustainable aviation fuel. Although it’s not yet available commercially, the company says it is on track to bringing its fuel to the global market and it will have its first commercial plant operating within 5 years. The company has already inked a partnership with the budget airline Wizz Air — the name of the company and the source of its potential combustibles could scarcely be a more perfect pairing — to supply it with fuel starting in 2028.

It currently sources its waste from water companies in the UK and takes the refined sewage through a process called hydrothermal liquefaction, which converts the liquid waste into a sludge or crude oil. Solid by-products can also be made into crop fertilizer. The company claims that the carbon intensity of the whole process — which measures how much carbon is needed to produce energy — is 7.97 grams of carbon dioxide per megajoule (gCO²e/MJ). Comparatively, the ICCT says carbon intensity recorded for jet fuel ranges from 85 to 95 gCO²e/MJ.

Organic matter, as the company points out, takes millions of years to develop into the fossil fuels that power cars and planes. Firefly’s solution makes it possible to generate fuel in a matter of days — and more importantly, human waste is a widely available resource. It’s unclear if sustainable jet fuel will be more or less expensive than what is currently available. The company could not immediately be reached for comment. However, in a statement, the company’s CEO James Hygate made mention that using human waste is a “cheap and abundant feedstock [that] will never run out.”

The achievement of carbon neutrality in our airspaces has been a longtime goal for regulators and leaders in Europe and the US. While EVs have made headway in the car industry, it might be a while before we see battery powered commercial jets. So in the meantime, solutions for creating more environmentally-friendly jet fuel are welcome.